the pure gain of ∆y – is equal to a difference of two compared levels, the subsequent and previous or initial, taken for base. If this base directly previous level, an indicator is called chain. If initial level is taken for base, an indicator call basic
At the agricultural enterprises of need for labor sharply increase during the spring and summer period. This need for the farms which are engaged in cultivation of agricultural cultures with the low level of mechanization of works is especially high.
In the direction correlation communications can be direct, the return, variable. At direct link the increase in a factorial sign is led on average to increase in a productive sign (at) and vice versa.
Due to the seasonal nature of agriculture the number of the collective farmers and workers occupied at agricultural works in winter months below than in the summer that it is more rational to use a manpower it is necessary to study seasonality of agricultural production.